"Sad Machine" is the second single and second song on Porter Robinson's album Worlds, released by the label Astralwerks. It features a duet between him (marking his vocal debut) and the Vocaloid AVANNA, making "Sad Machine" one of the first times a notable producer outside the Vocaloid community used a Vocaloid for more than just sound effects. Robinson based the song off the idea of a duet between a lonely robot girl and a human boy who finds her. The song was the last one written for the album, the release date of which was announced by newsletter subsequent to the song's release.